Thats what I was thinking too> It would have been great if I had something to put around it, but I left all my rock climbing stuff at home
never leave home without it.... What I like about it is you can build it to hold more weight smoothly if you think your going to need it after starting. The three main that I use is fo weights of 700lbs, 1400lbs and 1900lbs.
I know the military still teaches it I think they teach what you showed. I got this way of doing it from rope rescue classes that I had taken. But it is an international standerd class so I balive you could find it in a book someplace, I will have to look.